Water absorbent materials, such as superabsorbent polymers, can be employed in various applications such as in disposable sanitary products (i.e. diapers, incontinence articles, feminine hygiene products, airlaids and absorbent dressings), household articles, sealing materials, humectants in agricultural products for soil conditioning, in oil-drilling fluids (i.e. lost-circulation material, fracturing fluids), anti-condensation coatings, in agricultural, horticultural and forestry applications for retaining water in the soil and for the release of water to the roots of plants and trees, in the textile industry, in printing applications, in absorbent paper products, in bandages and surgical pads (i.e. wound dressings), in ore treatments, in pet litter, in water treatment, in food pads (i.e. applications related to the transportation of fresh food and food packaging), in detergents, in fire-fighting gels, in sealing materials, as chemical absorbents for the cleanup of acidic and/or basic aqueous spills including water soluble chemical spills, as polymeric gels for the slow and controlled release of cosmetics and pharmaceuticals (also known as drug delivery systems), as airlaids, and finally in the manufacture of artificial snow. However, the primary use of superabsorbent polymers, also referred to a “SAPs”, is in disposable personal hygiene products. Such products include, in increasing order of volume of superabsorbent materials used, diapers, training pants, adult incontinence products and feminine hygiene products.
Increased oil prices have had a negative impact on the superabsorbent industry such that natural polysaccharide-based superabsorbents have become an attractive alternative. Such natural superabsorbent materials can be readily obtained from renewable sources such as starch. Various absorbent compositions comprising polysaccharide-based superabsorbents have been proposed by Le Group Lysac Inc. Huppé et al. (CA 2,308,537) teach the use of biodegradable, glass-like pregelatinized starch as absorbents for liquids. Couture et al. (CA 2,362,006) teach the use of oligomeric polyethylene glycol crosslinked polysaccharides, in particular polyethylene glycol crosslinked starch as absorbent materials. Thibodeau et al. (CA 2,462,053) teach the use of crosslinked amylopectin as absorbent materials. Bergeron et al. (CA 2,426,478) teach the use of modified starches (i.e. crosslinked amylopectin) and mannose containing polysaccharides, ionic polysaccharides, gelling proteins and mixtures thereof in formulating absorbent materials. Berrada et al. (CA 2,483,049) teach the use of phylosilicates dispersed in an absorbent polysaccharide matrix, as having absorbent characteristics. Berrada (CA 2,519,417) teaches the use of guanidinated polysaccharides as absorbent materials.
The use of galactomannans, essentially cross-linked with borate, titanium or zirconium ions, as superabsorbent polysaccharides, has been disclosed in a number of patents: U.S. Pat. No. 3,661,154; U.S. Pat. No. 3,903,889; U.S. Pat. No. 4,624,868; U.S. Pat. No. 4,333,461; U.S. Pat. No. 5,532,350; U.S. Pat. No. 5,801,116; JP 2004-089401; JP 2004-075773; JP 2004-073370; JP 2004-066203; JP 2003-311150; JP 2003-154262; JP 2002-253961; JP 2002-035037; JP 2001-278998; JP 2002-037924; JP 2002-053859; JP 2001-120992; JP 2002-053859; JP 2001-226525 and JP 2001-122905. However, these polysaccharides suffer from syneresis and gel flowing problems. Crosslinking will seriously limit the manipulation of the absorbent materials, especially when shear thinning behavior is desired.
Complexes of aliphatic boronates with galactomannans have been disclosed by Bavouzet et al. (WO 97/47658). Complexes of aromatic boronates with galactomannans were disclosed by Bishop et al. (Dalton Transactions; 17; 2004; 2621-2634). PEG-diboronate galactomannan complexes have been disclosed by Coveney et al. (Molecular simulation, 2000, Vol. 25, pp. 265-299). Synthetic boronate polymer complexes with polysaccharides have also been disclosed by Miyazaki et al. (EP 0424168); Filipini (EP 0159521); Pelton et al. (WO 06/010268); and Destarac et al. (FR 2839723). However, these complexes were not disclosed as being absorbent materials.
There thus remains a need for absorbent hydrophobic boronate galactomannan complexes, as well as a process for producing same.
The present teachings seek to meet these and other needs.
The present teachings refer to a number of documents, the content of which is herein incorporated by reference in their entirety.